Chain stitch sewing machine



July 26, 1932. D. w. BUNKER CHAIN STITCH SEWING MACHINE Filed Oct. 11,1930 Wiinew' Patented July 26, 1932 v UNITED STATES PATENT OFFICE DARIUSW. BUNKER, OF QUINCY, MASSACHUSETTS, .ASSIGNOR TO UNITED SHOE MZA-CHINERY CORIORATION, OF PATERSON, NEW JERSEY, A CORPORATION OF NEWJERSEY CHAIN, STITCH SEWING MACHINE Application filed October 11, 1930.Serial No. 488,038.

The present invention has relation in general to chain stitch sewingmachines, and in particular to such machines wherein a shank needlecooperates with a cast-off in the stitchforming operation.

sirable to give the needle sufiicient strength and rigidity to penetratethe work. The shank needles heretofore used have been found to besatisfactory with thin work, but on thick work considerable trouble hasbeen occasioned by reason of theshoulder at the lower end of the shankengaging the castofi as the needle reaches the limit of its downwardstroke, and the cast-oft being then slightly impressed into the work,the lateral thrust imparted to the cast-ofi by the shoulder on theneedle tends to bend or break on its slender point.

In order to obviate this objectionable feature, the present inventioncontemplates the use of a needle having a cast-off engaging surfaceparallel to the path of movement of the cast-oft, at the same timeretaining the needle shank in the same dimensions as heretofore used. Asherein illustrated, the invention is embodied in a shoe sewing machineof the class known as McKay sewing machines in which the needlepenetrates the sole and enters the interior of the shoe and a horn isintroduced into the shoe to support the latter to carry thecomplementary sewing mechanism which cooperates with the needle informing the stitches. It is to be understood, however, that the presentinvention may be embodied in any chain stitch sewing machine wherein acast-oil cooperates with the needle in the stitch-forming operation.

Referring to the drawing illustrating the invent-ion in its preferredform, Figure 1 is a front elevation of the stitch-forming devices of ashoe sewing machine such as that illustrated in the patent to E. P.Richardson No. 710,612, dated October 7 1902, for.

shoe sewing machine, having the needle of the present invention embodiedtherein; Figure 2 is an enlarged View of the needle illustrated in thesame position as in Figure 1; and Figure 3 is a cross section taken onthe line 3-3 of Figure 2.

The needle, which is indicated at 4, has a shank 6 and a workpenetrating portion 8. As herein illustrated, the needle is cylindricaland has its work penetrating portion eccentrioally positioned relativelyto the shank, the periphery of the shank being tangent to the peripheryof the work penetrating portion along the cast-oil engaging surface 10.The cast-oil is shown at 12 at the lower extremity of its movement, thepoint of the cast-01f penetrating the work slightly in order to hold theprevious thread loop against fouling by the needle barb on the upstrokeof the needle. The needle is shown at the limit of its down stroke, inwhich position the lower extremity of the shank is close to the uppersurface of the work and the upper extremity of the needle engagingsurface 14 of the cast-off is on a higher level than the lower extremityof the shank (see Fig. 1). In shank needles heretofore enrployed, theshank has been made concentric to the Work penetrating portion of theneedle and consequently, when the needle and castoff were brought intothe relative position illustrated by Fig. 1, the shank interfered withthe cast-off and forced the cast-01f lat erally against the resistanceof the shoe sole, tending to break the tip of the cast-otl' point and toscrape the sole. The needle of the present invention corrects this faultby providing the straight surface 10 adjacent the cast-ofi whileretaining the needle" shank.

The nature and scope of the invention having been indicated and a needleembodying the features of the invention having been illustrated anddescribed, what is claimed as the invention is 1. A chain stitch sewingmachine having, in combination with the cast-off, a hook needlepositioned to engage said cast-off, said needle having a shankrelatively larger than its work penetrating portion and having acast-off engaging surface parallel to the path of movement of thecast-olf and extending above the lower extremity of the shank.

2. A chain stitch shoe sewing machine having, in combination with thecast-0d, a hook needle positioned to engage said cast-of said needlehaving a shank relatively larger than its work penetrating portion, saidshank and 5 work penetrating portion being eccentrically positionedrelatively to each other, the periphery of the shank being in alinementwith the periphery of the work penetrating portion along the line ofengagement with the m cast-ofi', and the cast-ofi' engaging surface ofthe needle extending above the lower extremity of the shank.

3. A chain stitch shoe sewing machine having, in combination with thecast-oft, a cyw lindrical hook needle positioned to engage saidcast-off, said needle having a shank relatively larger than its workpenetrating portion, said shank and work penetrating portion beingeccentrically positioned relago tively to each other, the periphery ofthe shank being tangent to the periphery of the work penetrating portionalong the line of engagement with the cast-oil, and the castoff engagingsurface of the needle extending 25 above the lower extremity of theshank.

4. A chain stitch sewing machine having, in combination, a cast-offconstructed and arranged to penetrate the work, and a needle positionedto engage said cast-off, said neeso dle having a shank relatively largerthan its work penetrating portion, and having a castott engaging surfaceparallel to the path of movement of the Cast-off and extending above thelower extremity of the shank.

35 In testimony whereof I have signed my name to this specification.

DARIUS W. BUNKER.

